Steel square



June 20, 41950 s, SHALER 2,512,177

sTEELsQUARE Filed Dec. 14; 194s 1N VEN TOR.

SAUL SNALS/2 H TTU/PNE Y Patented June 20. 1950 UNITED STATES FiATENT ..0 FF l CE.

STEEL SQUARE Saul Shaler,r Jackson Heights, N. ApplicationDecember 14, 1948A Serial No. 657,140

(o1. sez- 114) 3 Claims. l

This invention is a steel square,.fsuch as is commonly usediby carpenters and builders. These squares are madein various sizes, a very common size being one wherein one leg of the square is 2 feet inlength and the other leg 18 inches. A A square of'this size is inconvenient to carry in a journeyman carpenters ltool box and'isalso inconvenient ito package for shipment. There has therefore long existed a=very denite need fora knock-down steelfsquare, i. e., one in which the respective legs of the square may be dismantled for shipping or packing andv readily assembledfor use. l

Attempts have been made to provide such a square, but none ofthemhave proven satisfactory. They are Veither structurally so weak that they are too yeasily 'deformed or broken or are not or will not remain absolutely square It is essential that a tool -of the character under con sideration be accurate, i. e., that the legs of `the square be exactly atf90 with respect to one another. The slightest variationffrom this accuracy will render the tool ineffective for its intended purposes.

The-present invention fulfills along felt want in providing a square which ymay be 'economically manufactured, shipped or packed in knocked-down condition, and the parts of which may be quickly assembled into an absolutely ac.- curate tool, sturdy in construction and thoroughly efficient in use.

Generally speaking, the square of this invention embodies two legs of unequal length as here tofore, but these legs are made separate from one another and are adapted to be joined together at the angle of the square vbymeans of interlocking joints extending through the .full thickness of the stockvfrom which the legs of the square are formed. By preference the two arms are joined together in a 45 miter, each arm being provided at opposite sides of the miter with correspondingly shaped male and female joint elements such as dovetails, adapted to interfitand interlock with one Vanother and normally -secured in assembled relation by a locking .bolt ,v

passing through-a hole which overlaps two male elements of the joint. This bolt has an enlarged head and nut, both of which are underoutand the Opposite facesoi` the joint counterbored, so that there are formed'on the bolt and nut marginal ribs reecived `in the corresponding ychannels in the intertting velements of v.the yjoint. The joint as ,a whole is thereby reinforced, while the separate elements are firmly securedto one another by the vbolt. The exposed surfaces of 5s the yhead and nut are preferably substantially flush with the opposite faces ofthe square.' A square so constructed may Ybe quickly and easily dismantled or assembled and when in vassembled relation its parts willlbe lockedtogether so firmly that the accuracy of the included angle of the arms will be assured.

Features of the invention, other `than those adverted tc, will be apparent :from the rherein after detailed description and appended claims when read in .conjunction with the accompany* ing drawing.

The accompanying drawing-illustrates different practical embodiments of theinvention, but the constructions ltherein shown are to be under.- stood as illustrative, only, and not as defining the limits of the invention.

y'Figure 1 shows'a square embodying the present i invention slightly in perspective.

Figure 2 is a fragmentalview showing thearms of the square separated, so that the Yini'feritting joint elements of tl'ieseparts may-bemore clearly seen.

Figure 3 is a section onhthe line 3-3 of FigF ure 1. f

- Figure 4-shows amodied form of the inven-` tion. i

In the drawings, I designates Athe long arm of the square and 2`the short arm. IIx-practice this square isffabricated ufrom square edge stock with the parts .cut to length, hlanked, milled and broached by a series of simple conventional mallufacturing operations to produce this square with a minimum of operations which may be economically ,-performed.

In Figures 1 3 of .tn edrawings, thetwo arms of the square are'joined together nat 45 miller indicated at 3. This -miter determines, generally speaking, the pla-ne of symmetry of thev joint, this plane'being-normal to the planeof the faces of the square. Theeshort arm Ifisprovided along the miter `3 withV aprojecting dovelail 4 and a recess-5, the dovetail and recess being'of identical site and positioned atoppositesides of-therplane of'themiter. The long arm, lis similarly provided with a dovetailrprojection im and-a correspondingly shaped recess 5a which are likewise positionedfon opposite sides of the plane of the miter 3.

:It is advantageousto make both Qf the dove.- tailprojectionsfand the recesses of therespective parts of identical siriane-andV size and, to position them vin .complementary relation for, by sodoing, itispossible to blank and mill both parts through theuse ofthe same tools 1 and-thereby greatly econornize in manufacturing costs. When thus made, the parts 4 and 5 may be accurately intertted with the parts 5a and 4a, respectively, to produce a very close and accurate fit, so accurate in fact as to permit of no loss motion deviation in the angle of the square.

The joint elements are maintained in assembled relation by means of a bolt of special construction, comprising a head 6 and a nut 1, each of which is in the form of a relatively large plate. The head is undercut, as indicated at 8, to provide on its under surface an annular marginal bead 9 and the nut I is similarly undercut at I in its upper surface to provide an annular marginal bead II, said nut being also provided with a relatively deep hub I2 to receive the threaded shank I3 of the bolt.

This bolt is adapted to be passed through an opening collectively formed in the two dove tail projections 4 and 4a of the two arms, the portion I4 of the hole being in the dovetail projection 4 and the portion I4a of the hole being in the dovetail projection 4a. The opposite faces of both arms are bored coaxially of the bolt hole, so that the outer faces of the head and nut of the bolt may be substantially iiush with the opposite faces of the square, while an additional counterboring operation provides annular channels I5 and I5a coaxially of the hole and adapted to receive the beads 9 and II, as shown best in Figure 3. The channels I5 .and the beads 9 and I0 are made to accurately iit one another and thus serve to greatly strengthen the connection between the arms I and 2 and bind them firmly together, so that, if a great strain is placed on these arms, the dovetail joint elements will not be called upon to alone bear these strains.

A bolt has been described as used to bind the joint elements in assembled relation, but, if desired, the head 6 of the bolt may be in the form of a washer while the threaded shank or post may be in the form of a screw passed through the washer and preferably countersunk therein. This is optional. I prefer the bolt, however, as it results in less parts and, if desired, either the head or nut may be spot welded to one of the arms so that it will not get lost when the parts are dismantled. In .any event', a slot I6 is provided for the introduction of a screw driver by means of which the bolt may be attached or removed, a1- though an Allen screw hole or special wrench holes may be provided in either the head or nut portion of the bolt without departing from this invention.

In the structure oi' Figures 1-3, the joint between the` arms of the square is shown at a 45 miter at the angle of the square. If desired, however, the same type of joint may be made at right angles to one of the arms as shown in Figure 4, the parts being interlocked in the same manner as shown in the preceding figures and secured together by a bolt or screw as described.

In the accompanying drawings I have chosen to show the interlocking joint elements as of substantially dovetail conguration for I find this form of joint element peculiarly adapted for the present purposes. It is easy to manufacturel and machine to such closetolerances as are necessary to accuracy of the finished article. I may, however, employ other forms of interlocking joints, such as circular head, T-head or other similar types of joint which actually interlock to hold the elements of the joint together by virtue of the joint structure itself. Ordinary straight sided tenons will not do this for atenon can be readily withdrawn in the direction of its length and must depend upon extraneous fastening devices to secure it against withdrawal under stresses which would affect the accuracy of the square. A dovetail joint as well as similar interlocking joints are not open to this objection for they cannot be withdrawn from one another by a straight pull or by stresses circumferentially of the angle of the square. What is required is a locking joint which will permit disengagement of its elements in a direction normal to the face of the square and squares are not ordinarily subjected to such forces, at least such forces do not affect the accuracy of the square.

The present invention is therefore to be understood as contemplating the use of interlocking joints formed in the arms I and 2 in complementary relation to one another, i. e., joints which actually interlock of and by themselves against the forces which would change the angle of the square.

In the structure shown in the drawings, the bolt which maintains the joint elements against separation in a direction normal to the face of thesquare is so formed as to also reinforce the joint against changes in angular relation between the two arms of the square. This is the preferred form of the invention, although the invention is not necessarily limited to such a holding means as some other suitable holding means for maintaining the arms of the square in a common plane may be utilized without departing from the invention. It is also within the purview of this invention to employ the clamping means to the exclusion of the interlocking joint elements though this structure is not as satisfactory as the preferred form of this invention.

It will of course be understood that the square of this inventori may have stamped or otherwise delineated upon the faces of its arms, appropriate dimensional and other scales, such as are commonly found on steel squares, but these scales form no part of the present invention.

The foregoing detailed description sets forth the invention in its preferred forms, but the invention is to be understood as fully commensurate with the appended claims.

In the foregoing description I have referred to this invention as a steel square. These squares are generally made with both arms of the square of steel. However, in the garment industry, squares in the nature of steel squares are made with arms of wood joined together at the angle by metal ttings permanently secured to both arms. The present invention may be incorporated in such a square by mounting upon the wooden arms at the apex of the square metal ttings having interlocking joints and clamping plates as hereinbefore described. The invention is to be understood as fully commensurate with this concept and is not necessarily limited to an all steel square.

Having thus fully described the invention, what I claim as new and desire to secure by Letters Patent is:

1. A steel square comprising: arms arranged at righty angles to one another and occupying a common plane, each of said arms having a single male dove-tail joint element and a single female dove-tail joint element, with the complementary elements of both arms interntting one another to form a joint with its line of symmetry extending diagonally across the angle formed by the two arms, there being formed in the opposite faces of both arms coaxial annular channels which extend across said joint between said arms, a single bolt hole extending through both arms coaxially of said channels and intersected by the joint, and a single bolt having a shank extending through said hole with its head having a bead seated in the channel at one face of the square and its nut also having a bead seated in the channel at the other face of the square to rigidly hold the arms in said common plane.

2. A steel square as claimed in claim l, wherein the opposite faces of the arms of the square are recessed to receive the head and nut of the bolt to render the outer faces of said head and nut ush with said faces of the arms.

3. A steel square as claimed in claim l, wherein 15 both the head and nut of the bolt are circular and are recessed into the opposite faces of the square to be ush with said faces.

SAUL SHALER.

REFERENCES CITED The following references are of record inv the le of this patent:

UNITED STATES PATENTS 

